A primary focus of the UCSF-GIVI CFAR is HIV-related research that is both translational and multidisciplinary. The research often includes studies in which human subjects are the unit of observation and in whom complex biologic, behavioral, and clinical parameters are measured, often in a longitudinal manner. A prerequisite of human subjects research is the direct interaction with and exemplary characterization of both diseased and non-diseased research subjects. As such, the overall objective of the Clinical and Population Sciences Core will be to integrate the population sciences of epidemiology and biostatistics with the clinical science of HIV medicine to facilitate the interaction with and characterization of human subjects as well the analysis of the data and biological specimens derived from them. Fulfilling this objective in turn promotes multidisciplinary collaboration between laboratory-based and human subjectsbased researchers and is the sine qua non of translational research. Accordingly, the specific aims of the Core will be to support innovative human subjects-based HIV-related research by: 1. Providing expertise in the Clinical and Population Sciences related to HIV/AIDS research via consultation regarding conception of research questions, study design, data management, biostatistical analysis, and interpretation of data; 2. Serving as the resource clearinghouse for CFAR investigators who seek to perform new analyses with available data in the many large San Francisco-based and national studies of HIV-infected and at-risk individuals; 3. Managing a unique prospective observational cohort of HIV-infected adults in the contemporary era that provides translational researchers with a diverse array of biological specimens from subjects who are well-characterized in terms of clinical, behavioral, and epidemiologic parameters; 4. Providing a platform for the efficient conduct of newly designed prospective human subjects studies; 5. Mentoring junior investigators in the conduct of human subjects research. To achieve these aims, the Core will be directed by faculty with a wide range of experience in HIV-related research as well as methodological expertise in clinical research. In addition, the Core will serve as a link to related institutional resources at UCSF for human subjects research, including those in the Center for AIDS Prevention Studies, the Division of Biostatistics, and the Training in Clinical Research program. By achieving an economy of scale in its services, the Core will provide resource-efficient, flexible, and timely support to CFAR members as they pursue emerging opportunities in human subjects-based HIV/AIDS research.